Improvement of an SVC Using an Active Power Filter Connected in Parallel with Synchronous Switched Capacitors

This paper presents the solution for reactive power compensation and harmonic filtering by combining a shunt passive filter in series with a small-rated active filter and a synchronous vacuum circuit breaker with permanent magnetic actuator. The passive filter reduces the harmonic currents flowing into the source, and the active filter improves the filtering characteristic of the passive filter. An effective signal processing technique using the dq-transformation is applied to generate the reference signals for the controller of the active filter using the space vector pulse width modulation (PWM) technique. And a novel synchronous switching technology is proposed to avoid switching transients during the connection or disconnection of capacitors for power factor correction. Simulations and experimental results are presented verifying the excellent power quality improvement performance of the proposed topology while keeping the apparent power of the system minimal.